High frequency electric discharge tube



1.955 E. G. DORGELO HIGH FREQUENCY ELECTRIC DISCHARGE TUBE Filed Jan.. 4, 1951 INVENTOR.

EDUARD GERARDUS DORGELO AGENT United States Patent HIGH FREQUENCY ELECTRIC DISCHARGE TUBE Eduard Gerardus Dorgelo, Eindhoven, Netherlands, as-

signor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application January 4, 1951, Serial No. 204,415

Claims priority, application Netherlands January 10, 1950 3 Claims. (Cl. 313-254) This invention relates to electric discharge tubes having a cylindrical metal outer anode and one or more grids, a cathode, which is built up from a plurality of parallel wires or rods, being supported by supporting members which are secured to two rings or discs sealed in the tube wall and arranged at right angles to the tube axis, while the control-grid is supported by a central support which is sealed in the tube wall on the side remote from the electrode system.

In a known tube the control-grid is supported from a cylinder, of which it constitutes, as it were, an extension, the cathode being supported by two semi-cylinders from which a plurality of radial wings extend through apertures into the grid cylinders and which terminate at two leading-through discs.

The known construction has a limitation in that the cylinder constituting the extension of the grid has a high capacity relatively to the cathode and relatively to the support of the second grid. Such high capacities detract from the effect of the tube as an oscillator or an amplifier at high frequencies.

The object of the invention is to obviate the disadvantage stated above.

According to the invention, in a tube of the kind indicated in the preamble, the grid is supported by a central stud which extends as far as within the cathode and terminates in a number of radially protruding fins or rods, which support a ring to which the control-grid is secured. This ring is preferably arranged to surround the end of the cathode or other substantially non-emissive part thereof in order to avoid unnecessary damping.

This construction ensures effective screening between the support of the control-grid and the support of the second grid, whilst furthermore, the capacity between grid and cathode is not higher than is necessary. Moreover, conformation of the tube with a coaxial supply lead is thus materially simplified.

In order that the invention may be readily carried into effect, an example will now be described in detail with reference to the accompanying drawings, in which Fig. 1 is a sectional view taken through the axis of the discharge tube, and

Fig. 2 is a sectional view taken at right angles to the axis at the union between the grid support and the grid.

Referring to these figures, 1 designates the anode of the tube which, by means of a union piece 2 of poor heat conductivity, is sealed to the glass cylinder 3, to which is sealed a copper ring 4, which supports the support 5 of the screen grid 6. A further glass cylinder 7 supports the first cathode disc 8 and a third glass cylinder 9 supports the second cathode disc 10. The cathode stay rods are designated 11 and are alternately connected to the discs 8 and 10. The separate filament wires 12 of the cathode are secured to the flattened inner side 13 of the stay rods 11. The envelope of the tube is "ice completed by a glass head 14, to which the control-grid support 15 is secured. The control-grid support, which is shaped in the form of a stud, supports by means of three fins 17, by which star is formed, a ring 16, to which are secured the wires of the control-grid 18.

What I claim is:

1. A high frequency electric discharge tube comprising an anode, a cathode constituted by a plurality of parallel wires mounted to form a first cylindrical enclosure having a given axis, a metal disc having a central aperture sealed in a wall portion of said tube providing an external circuit connection to said cathode, a grid constituted by a plurality of spaced wires defining a second cylindrical enclosure interposed between said cathode and said anode, and a support for said grid, said grid support comprising a single rod extending through the wall of said tube along said given axis through the aperture in said disc and terminating within said first cylindrical enclosure, a hollow grid ring surrounding said cathode wires and secured to said grid wires, and a plurality of radially mounted members disposed between said cathode wires and connecting said ring to the end of said rod.

2. A high frequency electric discharge tube comprising a metal anode, a cathode constituted by a plurality of parallel wires mounted to form a first cylindrical enclosure having a given axis, a metal disc having a central aperture sealed in a wall portion of said tube providing an external circuit connection to said cathode, a grid constituted by a plurality of spaced wires defining a second cylindrical enclosure interposed between said cathode and said anode, and a support for said grid, said grid support comprising a single rod extending through the wall of said tube along said given axis through the aperture in said disc and terminating within said first cylindrical enclosure, a hollow grid ring surrounding a substantially nonemissive portion of said cathode wires and secured to said grid wires, and a plurality of radially mounted members disposed between said cathode wires and connecting said ring to the end of said rod.

3. A high frequency electric discharge tube comprising a metal anode, a cathode constituted by a plurality of parallel wires mounted on a plurality of rods and forming a first cylindrical enclosure having a given axis, said cathode wires being secured to the inner side of said rods, a metal disc having an aperture sealed in a wall portion of said tube providing an external circuit connection to said cathode and supporting some of said rods, a grid constituted by a plurality of spaced wires defining a second cylindrical enclosure interposed between said cathode and said anode, and a support for said grid, said grid support comprising a single rod extending through the wall of said tube along said given axis through said aperture in said disc and terminating within said first cylindrical enclosure, a hollow grid ring surrounding said cathode wires and secured to said grid wires, and a plurality of radially mounted members disposed between said cathode wires and connecting said ring to the end of said rod.

References Cited in the file of this patent UNITED STATES PATENTS 2,238,596 Mouromtsefl et al. Apr. 15, 1941 2,345,794 Chevigny Apr. 4, 1944 2,472,942 Drieschmann et al June 14, 1949 2,520,016 Ronci et al Aug. 22, 1950 2,544,664 Garner et al Mar. 13, 1951 FOREIGN PATENTS 327,634 Germany Nov. 2, 1920 

